Cooling system for internal combustion engines



July 6, 1937. s. w. RUSHMORE 2,086,441 COOLING SYSTEM FOR INTERNALCOMBUSTION ENGINES Filed Aug. 25, 1934 2 Sheets-Sheet 1 INVENTOR .SAMUELW Paw/mes Z BY 2 I I: ATTORNEY July 6, 1937. s. w. RUSHMORE COOLINGSYSTEM FOR INTERNAL COMBUSTION ENGINES Filed Aug. 25, 1934 2Sheets-Sheet 2 4 VIII/I/I/I/IIIII/I? H :1 vyv INVENTOR JIM/0E4 14/Posy/14025.

; BY I: ATTORNEY Patented July 6, 1937 PATENT OFFICE COOLING SYSTEM FORINTERNAL COM- BUSTION ENGINES Samuel W. Rushmore, Plainfield, N. J.

Application August 25,- 1934, Serial No. 741,396

2 Claims.

This invention relates to engine cooling systems of the class describedin my Patent No. 1,651,157, of November 27,1927, and, in my pendingapplication, Ser. No. 735,619, filed July 17, 1934, and has as its mainpurpose to permit or enable the employment of the system, as describedin the said pending application in cases where, owing to limitations ofspace or weight, it is impractical to employ a surge or reserve-watertank large enough totake care of the amount of water ejected by boilingin the water jacket, in operation of that system.

According to my present invention, the circulating system is sealed fromthe atmosphere. I thereby avoid or reduce the loss of water through theconstant breathing through the overflow pipe, and of antifreeze mixturesemployed in winter.

Also, where high output isdes'ired, with minimum 30 avoid an undesirablereduction in the boiling point under certain conditions such as reducedload. These relief and vacuum valves are preferably in:- corporated inthe water filling cap. I also provide an improved arrangement for 5employing the steam for heating the passenger space of a motor vehicle.I

I- may prevent all circulation in the cooling circuit until the waterjacket boils, by arranging an auxiliary tank supplying water to thesystem 40 at a level only slightly above the outlet from the waterjacket, so that the upper parts of the uptake'pipe and of the radiatorcore, as well as the upper tank of the radiator, are normally empty.When the water jacket boils, the pump plus, the

. 45 steam, start circulation and the empty upper part of the core for atime operates as a downflow condenser.

The above and other features of my invention may be more fullyunderstood'fr'om the following "50 v description in connection with theaccompanying drawings, in which Fig. 1 is a side .elevationconventionally indicating a common type of four-cylinderautomobileengine, to which my invention may be ap- 55 plied;

Fig. 1a is a transverse section through the upper chamber of theradiator and filler cap;

Fig. 2. is a plan view of the cylinder block showing the conventionalwater circulating passages connecting the cylinder jackets with the headjacket;

Fig. 3 is a section on the line 3-3, Fig. 1;

Fig. 4 is a section on the line 44, Fig. 3;

Fig. 5 is a side elevation of an engine like that shown in Fig. 1, butshowing certain modifications of the water supply means;

Fig. 6 is a section on the line 66, like Fig. 3 except with thethermostat and valve omitted;

and

Fig. '7 is a section on the line 1-1, but without 15 the thermostat andvalve.

In these drawings like parts are indicated by like numerals; and theparts similar to those in my prior application Ser. No. 735,619, are asfollows:

The upper ends of engine cylinders l are surrounded by the conventionalwater jacket 2 communicating through openings 3, 3, with the waterjacket space 4 of the head block 5. The cooling circuit includes theuptake pipe 6, discharging into the upper header or tank 1, throughwhich the water and/or steam cooling medium flows downward through thehoneycomb or tubular air-cooled conduits 8 to the bottom tank 9 andthrough return conduit ID, to the water jacket of the head. The airdraft is drawn through the radiator cooling elements 8 by fan I I onshaft l2 and is driven from the engine by belt I3. Circulation of waterthrough the above circuit is assisted by a suitable pump, in this casearotor I4 such as commonly employed on the Ford motor to assistthermo-circulation of water from the head jacket and into the uptakeconduit 6. The pump could be located in the low level part of returnconduit ID, as is more common, but there are advantages in employing thehigh level suction pump in connection with my present invention, whichwill be explained in due course.

Means for utilizing the cooling capacity of this circuit so as to ensureboiling in the water jacket under average conditions, without danger ofescape of steam under special conditions of maximum heat evolution inthe cylinder, includes a chamber I6 into which the pool water returnpipe I!) discharges, and fromwhich the-uptake pump I4 assists flow ofwater into the uptake conduit 6. As shown in Figs. 3 and 4, this chambermay be formed by a side wall l1, and end wall l8,the roof of thecombustion chamber l9 constituting the bottom of the chamber and the topbeing closed in as by a plate 20. As in my said patent and pendingapplication, this chamber not only provides a short circuit-completingpath 'fromtheretum pipeto the uptake conduit 6, but hasfluid-interchange communication with the head jacket space throughone ormore suitably restricted openin s as at 2 i, said opening or openingsbeing preferably in the wall of the chamber which is opposite.

the intake of the pump. As indicated by the arrows, the water supplytothe jacket flows out through 2! and steam or hot water can fiow'incylinder jackets are actively boiling, the flow will be pulsating,steam or steam-foamed hot water flowing from the head jacket intochamber l6 and then water'from chamber l6 flowing into the head jacket.The latter is like the ordinary geyser effect which results from boilingat the bottom of the cylinder jacket where the water is subjected tosubstantial depth pressure.

. The flow of the cool water from pipe l0 through inlet opening Illa,may be controlled, if desired, by an inlet valve lb carried by athermostat 23, as in said application Ser. No. 735,619. This thermostatis preferably of the metallic bellows type,.containing a liquid boilingat a temperature corresponding to that which it is desired to maintainin the chamber i6. As is well known in the art, the boiling point of agiven liquid contained in the thermostat, may be varied somewhat by'changing the-pressure within the, bellows, either when charging it orby applying'adjusting exter- -nal spring pressure after the bellows issealed.

Preferably a stop, 25, is provided to limit expansion of the bellowsbeyond wide open position of valve iflb. v

Special features of the design and operation of my above describedapparatus, are as follows:

The pump l4 operates continuously at speed proportional to .the speed ofthe engine. 1 Upon starting the engine cold, the cool water inlet I0 isclosed, so that there is no circulation through the.

I cooling circuit, and, at first there is practically no interchange ofwater between the chamber l6 and the water jackets. At this stage onlythe water in the water jacket is being heated. As the jacket water heatsup, there begins to be increasing thermocirculation through restrictedcornmunication 2 I; and, by the time'jacket water is near boiling, thewater in the chamber I6 will be heated to its normal minimum, for whichthe thermostat is set. Thereafter, variable condensing and boiling inthe bellows, will tend to cause closing or opening movements of valvelilb, ac

. cording as the temperature of the fluid mixture in chamber l6, risesor falls. Alternately, with increasing load, the bellows will open thevalve wide and thereafter, with further increase in load and steamevolution, the valve will remain wide open but the temperature of thecooling medium in the compartment IE, will be controlled by boiling inthe jacket and condensing in the boiling circuit. The new featurescharacteristic of my present system are as follows:

Fig. 1a. is an enlarged detail of the top tank I having a filler cap Ia,on tube 1b in which is the -'uppe-r end of the usual overflow pipe I5.The

pipe is sealed in and communicates with the radiator tank only throughthe opening 10, which engine jacket atabout atmospheric pressure whilethe pressure in the top tank will generally be somewhat higher,depending upon the speed of the pump and also the amount of openings ofthe thermostat-controlled valve.

In the arrangement described in my pending application there being nopressure in the top, tank, the water flow and, to some degree, thepressure or vacuum in the engine jacket will vary with the pump speed;With the present arrangement, however, discharge of water displaced bythesteam bubbles in the engine jacket will be opposed by the pressurerelief valve and a pressure will pile up in the top tank and in theradiator depending'upon the amount ofthermostat valve opening and uponthe characteristics of the centrifugal pump.

In the case of the Ford-8, for example, using the standard Ford radiatorand an eflicient pump, under maximum load and speed, the waterdischarged through each engine jacket will not much exceed one halfgallon, and therefore I have not,

found it necessary to employ other than the standard Ford radiator andtop tank.

Of course, the top tank should be normally the outlet 6, from the pumpM. This cock may be left open while water is poured in to fill thesystem and water flows out of said cock; then allowing it to drain ofito the level of cook 30. This may leave some excess water in theradiator part of the system, butthe thermostat is designed to keepvalvelllb closed until the water boils in the jacket, and such excess may beeither blown out through the filler cap by the above describedintermittent geyser-like discharge of steam and water; ,or preferablycock 30 will be left open and the engine stopped and re-started to openand close the valve lflb, water being drained off or added, as shown tobe necessary by the test cock. As a practical matter, excess water willalways take care of itself by blow-'ofi, asabovedescribed,

and the necessary thing is to provide means for refilling to the levelof the cock.

To maintain this normal water level I provide an auxiliary tank 3!,which discharges through .pipe 32 into uptake pipe 6, at the level ofcook 30. It operates on the bubble principle. That is to say, it ishermetically sealed at the top and Water can flow out at the bottom onlyas air or gas bubbles back through said Pipe, which can occur only whenthe outlet of said pipe is uncovered by loss of water. For conveniencein filling this auxiliary tank, I provide an outlet valve 33, in thebottom of the tank, normally closed by spring 34, whenever the cap 35 isremoved. The tank is filled while the valve is closed and when the cap35 is replaced it operates through stem 36 to depress the valve and holdit normally open for operation on the above described bubblebackprinciple. a

It will be evident that with this arrangement or tank 1 and parts ofuptake pipe 6 and core 8 sol above the normal water level, there will bea gap in the water circuit, the pump 4 being primarily designed merelyfor assisting thermo-circulation through the circuit when theupper tankis full of water. Consequently, with the present empty gap in the upperpart of the circuit, such pump steam in combination with the pump, isable to lift the water in uptake pipe 6 to the level of tank I, whenceit can flow down into radiator core. 8.

It results that at low load, the flow of coolin fluid from the waterjacket to the top tank of the radiator may be mostly steam, which willbe condensed partly in said top tank and partly by downfiow into theempty upper part of the radiator core 8. However, a steady state seemsto be unusual, and I have observed that in practice,

instead of a steady outflow of steam from the engine jacket throughopening 21 to the short circuit compartment i6 and a correspondinglysteady return flow of water,there is a more or less violent breathing orpulsating action through the opening 2|. Consequently, there is asimilar tendency to pulsation in uptake pipe 8 so that the proportionsof steam or steam bubbles and foam and/or water mingled therewith, mayvary widely.

I have taken advantage of the pulsating action between the engine jacketand compartment I 6, through constricted opening ii, to cause a flow ofsteam through a heater for the passenger space of the car. This isaccomplished by connecting a pipe 40 from the top of the water jacket,preferably at the rear thereof, to the top of the radiator 4| located inthe car, a return pipe 42 being connected to the top of the compartmentHi. This takes advantage of a pressure differential due to theconstriction and also of the above described pulsating effect. A suddeninstantaneous rise in pressure in the jacket, seems to force a quantityof practically weightless steam from the rear cylinder head into the carheater; but, owing to its inertia, the water inthe return pipe tocompartment I6 remains relatively stationary during such pressurepulsation. However, the broad claims for the car heater and circuittherefor, through which steamis caused to flow around a constrictionbetween the water jacket and the uptake pipe, have been transferred tomy copending application Ser. No. 13,186, filed March 27, 1935, which,among other things, shows and describes a similar constriction and asimilar heater circuit similarly arranged.

Referring more in detail to the pressures employed in the coolingsystem, I maysay that the pressure relief valve 1d may be designed oradjusted for opening at a pressure of, say, four or five pounds, whilethe vacuum relief valve should open at very slight vacuum, preferably aninch of mercury, or less. I find that even under a full sustained load.with a maximum jacket pressure of 5 pounds, not more than twoquarts ofwater will be expelled from the engine jacket even when initially filledfull of water; and by filling it only about half the height of theradiator. there will be no loss of water, under the hardest running.

Although most of the time there will be little or no pressure in the toptank, so that the radiator cap may be removed without danger, there maybe times. as when stopping suddenly at top of a long hill, or wherethere is an accumulation of air in the tank. with the engine onlyidling, when removal of the cap might permit a small outrush of hotwater or steam. I therefore provide one or more holes, in the fillertube which will be uncovered and permit a slight outflow of air. steamor water to relieve the pressure and also to give ample warning not tofully remove the cap until the pressure has ceased.

From the above it will be evident that the pressure relief and vacuumbreaking valves may be used either where the system is full of water orwhere it is maintained at a low level, as for instance that of cock 30in Fig. 1. In this connection. it is to be noted that the thermostaticvalve is mainly of importance where the system is nearly filled withwater. When the cooling circuit is broken by a gap at the top, due to'low level of water in the system, the thermostat 23 and valve lob arerelatively useless and may be omitted, as in the modificationillustrated in Figs. 5, 6, and 7. In Fig. 5, the engine is shown thesame as in Fig. 1, and the water cooling circult is the same as concernsuptake pipe 6, top tank I, radiator core 8; bottom tank 8, return pipeI0, fan H, shaft i2 and pump l4. Also the auxiliary water supply tank3i, pipe 32, valve 33, spring 34, cap 35, rod 36 and bubble pipe 32 arethe same and the connection of the latter is at the same level with thecock 30.

The internal arrangements shown in Figs. 6 and 7 are also the same asconcerns shaft i2, pump i4, compartment l8, closed in by walls i1, i8,with the top of the combustion chamber forming the bottom I! and theplate 20 closing in the top thereof. The only difference is that thethermostat and valve are omitted from Figs. 6 and 7. In Fig. 5, theradiator connection is omitted for convenience in illustration. It willbe noted, however, that the filler cap Ia with its pressure relief valve1d and vacuum breaking valve if, is located on top of an auxiliary surgetank 1y which communicates with the main top tank 1 through pipe la. Thevent pipe lia corresponds in function to the overflow pipe l5 of Fig. 1and Fig. 111. As before explained, the gap in the cooling circuit abovethe level of cook 30, in combination with the pump l4, compartment [6,and construction 2|. render the thermostatic valve unnecessary. a

I claim: p

1. A cooling system for internal combustion engines, including a waterjacket for the engine, a cooling circuit including a downflow, aircooledradiator having a core extending above the top and below the bottom ofthe jacket, an upflow pipe to the upper part of the radiator, a returnpipe and a pump to assist water circulation in said circuit; meansassociating said cooling circuit with the water jacket, including achamber providing a short circuit-completing path between the lower endof the upflow pipe, and the upper end of the return pipe, and whichcommunicates with the upper part of the engine jacket only throughrestricted flow paths; and means for predetermining an initial waterlevel in said circuit that is substantially below the level of the topof the radiator core so that the water surfaces in upfiow and downfiowpaths of the circuit are normally separated by a gap of height too greatto permit circulation by the pump until assisted by boiling in the waterjacket.

-2. A cooling system for internal combustion engines, including a waterjacket for the engine, 5 a cooling circuit including a downflow,air-cooled radiator having a core extending above the top and below thebottom of the jacket, an upflow pipe to the upper part of the radiator,a return pipe and a pump to assist water circulation in 10 said circuit;means associating said cooling circuit with the water jacket, includinga chamber providing a short circuit-completing path between the lowerend of the upflow pipe, and the upper end of the return pipe, and whichcom- 15 municates with the upper part of the engine jacket only throughrestricted flow paths; means for predetermining an initial water levelin said to automatically vent internal pressures a predetermined amountabove atmospheric, and another opening inward andvset to automaticallyrelieve subnormal pressures a predetermined amount below atmospheric.

SAMUEL W. RUSHMORE.

